The International Association for Comparative Research on Leukemia and Related Diseases (IACRLRD)---with secretariat offices at the Harvard AIDS Institute of the Harvard School of Public Health-- is requesting financial support from the National Cancer Institute for the International Symposium on HIV, Leukemia, and Opportunistic Cancers, the IACRLRD~S twentieth symposium. This meeting will be held at the Palais des Congres de Marrakech, Marrakech, Morocco, May 23-28 1999. Dr. Myron Essex, IACRLRD president will serve as the host and symposium chair. Funds are requested for the travel expenses of invited speakers, session chairs and scientific session chairs from the United States. No funds are requested for Symposium personal. From its inception, the IACRLRD has stressed the importance of comparative studies in humans and animals with particular emphasis on retro viral diseases. Its symposium series, which is held every two years has been the principal forum for the exchange of research information on leukemia and retro viral disease and a major opportunity for researchers to share current developments in the understanding of HIV and AIDS. The Symposium will emphasize biomedical science and research, with the scientific sessions following one of there thwacks: HIV and Other Retroviruses, Leukemia and Other Cancers, and Opportunistic Cancers in Relation to Immunosuppression and Other Issues. Sponsoring this meeting is of particular importance in today~s fast- changing world of biomedical research. With the advent of combination chemotherapy for HIV, people who can afford such drugs can be kept alive for prolonged periods. Certain forms of leukemia were already known to occur at elevated rates in AIDS patients, and researchers may expect their rates to increase as AIDS patients are kept alive for longer periods. Therefore, focusing the Symposium on the comparative and complementary aspects of these disease will provide scientists and clinicians with the knowledge and skills to better adapt their efforts to discovering techniques to treat, and eventually, cure those living with HIV, AIDS, and cancer. The Symposium scientific program will combine round table discussions, plenary addresses, abstract presentations, IACRLRD memorial lectures, and parallel scientific lectures by some of the science~s most renowned and accomplished researchers . All sessions will include a question and answer period. The Symposium will have open enrollment and interested participants are invited to submit abstracts for oral or poster presentation. Attendance will be limited to 1,000 registrants.